calculateAvailableSplitters

This function calculates how many splitters it could create based on expected average tasks per
RS and the hard limit upper bound(maxConcurrentTasks) set by configuration.
At any given time, a RS allows spawn MIN(Expected Tasks/RS, Hard Upper Bound)

taskLoop

Wait for tasks to become available at /hbase/splitlog zknode. Grab a task one at a time. This
policy puts an upper-limit on the number of simultaneous log splitting that could be happening
in a cluster.

Synchronization using taskReadyLock ensures that it will try to grab every task
that has been put up